1. Technical Field
This invention relates generally to knives, and more particularly to a convertible knife that can be used as a conventional fixed-blade knife and as a blade-and-anvil cutters.
2. Description of Related Art
A conventional fixed-blade knife is a cutting tool having a blade and a handle attached to the blade. The blade has an edge (a cutting edge) that extends from the handle end of the blade (the proximal end portion) toward the tip of the blade (the distal end portion), and a spine (the top of the blade) opposite the cutting edge that also extends from the handle end of the blade toward the tip of the blade. The spine of the blade is typically somewhat broad (at least near the handle the end) so that a user can push against it with his thumb in order to facilitate cutting with the edge of the blade. Hunting knives and kitchen knives are good examples.
Whether in the field, in the kitchen, or elsewhere, some cuts are better made with a blade-and-anvil type of cutters (i.e., a cutting tool having a blade that closes and cuts against an anvil). The blade-and-anvil cutters in U.S. Pat. Nos. D398499, D434955, D422463, and D427036 provide good examples. But, a second tool is required and so it is desirable to have a better way to accomplish these two different types of cutting.
This invention addresses the concerns outlined above by providing a convertible knife that can be used for both types of cutting. The convertible knife includes a knife member and a companion conversion member that locks onto the knife member when desired. Preferably, at least a portion of the spine of the knife is sharpened to provide a secondary cutting edge, and the conversion member locks onto the knife member pivotally to provide an anvil member that works in opposition to the secondary cutting edge. Thus, the user can quickly convert between knife stye cutting and blade-and-anvil cutting by adding or removing the conversion member.
To paraphrase some of the more precise language appearing in the claims, a convertible knife assembly constructed according to the invention includes a knife and a conversion piece. The knife has a handle and a blade. The blade includes a proximal end portion attached to the handle, a distal end portion, a cutting edge intermediate the proximal end portion and the distal end portion, and a spine intermediate the proximal and distal end portions that is disposed opposite the cutting edge. The knife may be similar in many respects to existing fixed-blade knives.
The conversion piece has a spine-opposing portion and a handle portion. It is adapted to be mounted on the knife pivotally with the spine-opposing portion opposing the spine of the blade and the handle portion opposing the handle of the knife. The action of a user squeezing the handle portion of the conversion piece and handle of the knife toward each other causes the spine-opposing portion of the conversion piece and the spine of the blade to move toward each other in order to bear against an object the user positions between the spine-opposing portion and the spine of the blade.
In one embodiment, the spine of the blade includes a sharpened portion that forms a secondary cutting edge, and the spine-opposing portion of the conversion piece forms an anvil facing the secondary cutting edge. That arrangement enables blade-and-anvil cutting of the object. In another embodiment, the spine-opposing portion of the conversion piece forms a conversion piece cutting edge opposing the secondary cutting edge of the blade in order to enable shears-type cutting of the object. In yet another embodiment, the spine-opposing portion of the conversion piece forms a dull edge facing the spine of the blade in order to enable crimping of the object.
Preferably, the conversion piece includes a mid portion that defines a channel into which the blade of the knife fits. The mid portion includes a pin extending across the channel that defines a pivot point, and the blade of the knife defines a recess adapted to engage the pin. A spring-loaded hook assembly on the conversion piece engages a protrusion on the blade as the blade is inserted into the channel, so that the hook assembly spring biases the blade toward the pin as the pin seats in the recess.
Thus, the invention provides a convertible knife that the user can readily disassembly for independent use of the knife and for cleaning purposes. The following illustrative drawings and detailed description make the foregoing and other objects, features, and advantages of the invention more apparent.